1. Field of the Invention
The present invention relates to a method of minimizing NO.sub.x emissions in the combustion of a fuel in a furnace installation fitted with at least one burner. It also relates to a burner for carrying out the method.
2. Discussion of Background
In the combustion of oil, gas and other fuels of high calorific value, the waste gas compositions are subject to increasingly stringent statutory regulations with respect to the pollutants formed. Thus, for example, in the operation of a gas turbine, above all the adherence to the regulations concerning the maximum permissible NO.sub.x emissions causes great difficulties. To adhere to these nitrogen emissions, it is usual to spray water into the flame in the combustion of the said fuels of high calorific value, with the final purpose of thus reducing the nitrogen oxide emissions. By means of this water feed, the hot zones in the flame are cooled, in such a way that the NO.sub.x production, which is extremely dependent on the maximum temperature which is reached, can be reduced in this way. In this connection, attention is drawn to the literature reference by Arthur H. Lefebvre, Gas Turbine Combustion, McGraw-Hill Series in Energy, Combustion and Environment, New York, pages 484 et seq. A problem in this method is the fact that the water fed frequently also interferes with flame zones which by themselves produce little NO.sub.x but are eminently important to the flame stability. Thus, large areas of the ignition zone, where freshly fed fuel/air mixture must continuously be ignited anew, are quenched by the conventional fine atomization of water which is also recommended by Lefebvre. As a consequence thereof, instabilities occur, such as flame pulsations and/or poorer, for example streaky burning in the combustion process, the effects of which are responsible for a rapid increase in the CO output.